A single pointing, 3-band, near-infrared image, obtained with Gemini South’s GeMS/GSAOI of the star cluster and associate nebula R 136.

Despite years of study with the largest telescopes and best instruments, the nature of star cluster centers is not well understood. The best data to date from the Hubble Space Telescope on R 136, a local analog to starburst clusters in distant galaxies, are still incomplete. The crowded fields make it difficult to count all the stars in the core due to the extensive overlapping of suns. With GeMS, astronomers can now resolve most of R 136’s core down to one or two solar masses and determine if stars less massive than this prevail. “Having a wide field of view with uniform image quality makes such investigations easier and more accurate than could be done before,” said National Optical Astronomy Observatory’s deputy director, researcher, and principal investigator, Robert Blum. “Using GeMS, we can obtain the very best description of the stellar content of R 136 ever. Not until the next generation of large ground-based telescopes are built will we be able to do better.”